Electromagnetic wave reflectors are used in the design of antennas in the telecommunication field. The antennas are in particular used in space applications to equip telecommunications satellites. An antenna with a conventional configuration is composed of a radio frequency source and a reflector with a parabolic form whose concave reflector surface constitutes the active surface. A source is placed at the focal point of the reflector and is designed to emit or receive electromagnetic radiation focalized by the reflector. The reflector can also have other shapes than parabolic, e.g. convex or numerically determined.
There is a strong demand for large size reflectors. These types of reflectors enable communication over greater distances and the reception of weaker signals relative to the noise level, or to transmit with a greater gain signals from high power sources. The gain of a reflector is directly related to its area subtended by the reflector in a plane perpendicular to the axis of the reflector. However, in any type of space application there is always a need for weight optimization. It is therefore essential to find a reflector which may be made light-weight without losing the required electromagnetic properties.
One known design of a thin, light-weight reflector consists of a reflector dish of fiber reinforced plastic material supported by a backing structure or support structure. The support structure has the function of supporting the reflector dish and also of contributing to the rigidity of the reflector structure. U.S. Pat. No. 4,862,188 describes such a reflector having a shaping structure and a reflecting mirror placed against the structure, where the supporting structure is a lattice arrangement. This type of reflector dish allows for a light-weight construction of an antenna with good thermoelastic behavior.
U.S. Pat. No. 2,747,180 discloses a reflector with a honeycomb core. The reflector construction gives a light weight and rigid reflector that does not require a separate support structure. The reflector is a sandwich construction which may be manufactured by performing multiple operations in a mould tool.
However in spatial applications, the antennas need to be as light as possible so as to facilitate the placing in orbit of a satellite equipped with antennas with reflector dishes. It would therefore be beneficial to further reduce the weight of the reflector, while ensuring the required stiffness of the reflector dish.